1. Field
The present disclosure relates generally to aircraft and in particular to aircraft control surfaces. More particularly, the present disclosure is directed towards a computer implemented method, apparatus, and computer usable program product for manipulating control surfaces to reduce aircraft wing-body loads.
2. Background
Control surfaces, also referred to as flight controls or actuators, are airfoils that deflect air in one direction and cause an aircraft to move in the opposite direction. As used herein, an aircraft includes, without limitation, an airplane, a helicopter, a carrier, a commercial airliner, a sea plane, or any other type of aircraft.
Control surfaces are manipulated by pilots or by control laws to move an aircraft about its axes of motion and/or change an orientation of the aircraft. Control surfaces are frequently manipulated by using a control yoke, control stick and/or pedals, such as a rudder pedal. Control surfaces may also be manipulated by control laws and logic.
Control surfaces include, without limitation, ailerons, flaperons, rudders, spoilers, elevators, trim devices, and flaps. The ailerons, spoilers and flaperons are used to bank or roll an aircraft about the aircraft's longitudinal axis. The rudder yaws an aircraft about a vertical axis. The elevator moves an aircraft about the aircraft's lateral axis to change the aircraft's pitch attitude. Utilization of symmetric flaperons results in vertical motion of an aircraft.
Load factor is the ratio of total lift generated by an aircraft to the total weight of the aircraft. The lift is generated by the motion of air over the wing surface. Larger wings move more air over the wing surface. A larger wing relative to the wing mass will typically have a lower wing load. The wing load is generally expressed as acceleration due to gravity (g).
In straight and level flight, the total lift of an aircraft is equal to the total weight of the aircraft. In such a case, the load factor is one (1.0) gravity. When an aircraft is maneuvering, wing lift is diverted to performing the maneuver. Maneuvering may include turning, banking, changing pitch, inverting, and/or changing orientation. For example, when an aircraft performs a turn, the aircraft's lift vertical component, which is against gravity, is reduced and results in a descent. To compensate for the descent, the lift force is increased by increasing the wing angle, which results in an increase in drag. This results in an increase in the load on the wings.
Thus, the maneuverability of an aircraft may be limited by the wing size, the available engine power, and the maneuver load on the wings. Moreover, increases in maneuvering loads on the wings may increase fuel consumption and/or decrease flight speed.